Stimulation fluids, such as hydrocarbon-based fracturing fluids are used to treat formations by introducing the fluid into the formation, typically using specialized tools, through a wellbore.
In the case of fracturing fluids, the fluids are typically designed to carry a proppant, such as sand, which is deposited in fractures in the formation produced as a result of hydraulic fracturing with the fluid. The proppant maintains the fracture through which formation hydrocarbons are produced to the wellbore.
Additives are generally added to a hydrocarbon-base fluid to create a fracturing fluid having an increased viscosity so that sufficient proppant can be carried into the fractures. In most cases the increase in viscosity or gelling is reversible, such as through the use of breakers which can be time delayed or activated such as by a change in pH or the like.
At least a portion of the fracturing fluid is produced from the wellbore and generally contains a variety of contaminants carried therein from the formation and the wellbore. The contaminants may include, but are not limited to water, hydrocarbons, such as C1-C6 light hydrocarbons, C15 and greater, or C20 and greater hydrocarbons, gelling additives and other contaminants, such as organometals and the like.
Conventionally re-refining of used oils has been accomplished using distillation in a fractionation tower. It is known however that due to presence of gellants and other additives in the returned fracturing fluid that fouling of the towers occurs.
There is interest in the industry in recycling at least the hydrocarbon base fluid produced from the wellbore, such as through removal of the contaminants therein to permit reuse of the hydrocarbon base fluid in a variety of different uses, including the preparation of new fracturing fluid.